This study will test the hypothesis that intraoperative measurement of the transverse (horizontal) Young's modulus of the human vocal folds will improve phonosurgical results for glottal incompetence caused by unilateral vocal fold paralysis. An existing prototype device will be modified and used to measure Young's (elastic) modulus of the vocal folds during augmentation by Teflon injection. In the first phase of research, Young's modulus will be measured in patients after Teflon injection during their surgery. Their vocal function will then be tested six weeks after surgery using videostroboscopic measures and perceptual judgments. In the next phase, patients who receive vocal fold augmentation will be randomized into three groups and the results of their surgery on vocal function will be compared. In one group, the Young's modulus values associated with the most successful surgical results in Phase 1 will be used as target values during surgery. In the second surgical group, the Young's modulus of the unaffected vocal fold will be determined by using transtracheal stimulation to simulate normal muscular contraction and glottal configuration during phonation. This modulus value will then be used as the target for the degree of vocal fold augmentation of the affected vocal fold. The third group will serve as a control group and will have surgery without the aid of intraoperative monitoring of a target modulus. The device to measure Young's modulus will then be evaluated as a tool for intraoperative optimization of phonosurgical results by comparing various acoustic, glottographic, aerodynamic, videostroboscopic, and perceptual measures before and after surgery.